Windows Vista 32bit continuously freezes temporarily

[JCubed]

For some reason my comptuer is freezing at an increasing rate. It freezes temporarily for 20-50 seconds, and does that at random intervals. It doesn't matter how much processor or memory is being used. It started off slow here and there, and then began to hit before I even logged on. It doesn't do anything while I'm in the windows vista cd boot menu, or while I'm in safe mode. Though yesterday it did freeze on boot up before I even got to the windows boot menu.

When first began to freeze I did an Eset Nod virus scan, and a malware bytes scan (I also have threatfire constantly running), then a startup files fix, and a memory diagnostic with my windows Vista cd. All found nothing. Then it booted up to a checkdisk and it froze giving me a BSoD about some nvidia driver, so I went and downloaded the latest drivers, and that did nothing. Then it did a checkdisk again, and got through without any BSoD and made some fixes, but that didn't stop the freezing. I also did a PC tools registry scan, and fixed some problems there, and it still didn't stop the freezing.

I'm wondering if it's my power supply.

It seems to be getting worse and worse and I don't know what it might be or how to fix it. I'm going to uninstall any programs that I've installed recently as well and see if that works.

Here's the specs:
1 x EVGA 122-CK-NF63-TR LGA 775 NVIDIA nForce 680i SLI ATX Intel Motherboard - Retail
1 x EVGA 768-P2-N831-AR GeForce 8800 GTX 768MB 384-bit GDDR3 PCI Express x16 HDCP Ready SLI Supported Video Card - Retail
1 x CORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model TWIN2X2048-6400C4 - Retail
1 x G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model F2-6400CL5D-4GBPQ - Retail
1 x Antec TPQ-850 850W Continuous Power ATX12V / EPS12V SLI Certified CrossFire Ready 80 PLUS BRONZE Certified Modular Active PFC "compatible with Core i7/Core i5" Power Supply - Retail
1 x Intel Core 2 Quad Q6600 Kentsfield 2.4GHz LGA 775 Quad-Core Processor Model BX80562Q6600 - Retail
1 x ASUS 18X DVD±R DVD Burner with LightScribe and 14X DVD-RAM Write Black SATA Model DRW-1814BLT LightScribe Support - Retail
1 x Creative Sound Blaster X-Fi XtremeGamer Fatal1ty Pro 7.1 Channels PCI Interface Sound Card - Retail
and 2 500 gig hard drives.